what happens when a function with static variable called by multiple thread?

Question

Suppose there is a function :

Obj* Obj::instance()
{
   static Obj obj;
   return &obj;
}

As we known that obj will be initialized when Obj::instance has been called for the first time. But what will happen if multiple thread call this function concurrently?

Answer 1

Thread with the highest priority gets a lock on that variable!